The expense of transporting and setting up drilling rigs at different drill sites can be time consuming and costly. Transporting the equipment for drilling oil and gas wells is often costly because such equipment is heavy and bulky. For example, modular drill rigs often include a mast of over a hundred feet when fully erected, a drilling floor, and a substructure to support the drilling floor and mast. The substructure raises the drilling floor off of the ground at a sufficient height to accommodate drill equipment connected to the well bore, such as a blowout preventer.
Transporting the rig generally includes disassembling the components of the drill rig into manageable loads that meet government regulations for transport on truck beds and trailers. At the new drill site, the rigs are assembled in place before the well head equipment is positioned in place.
One type of modular rig is disclosed in U.S. Pat. No. 8,720,128 issued to Dewayne G. Vogt. In this reference, a method to disassemble a mast assembly having a substructure including a first and second section, a first and a second cylinder, and a lower mast section. The method includes the steps of disengaging a pair of front mast legs of the lower mast section from a pair of front leg supports. The pair of front leg supports are moved from an operational to a transport position. The lower mast section is lowered from a vertical to a horizontal position by retracting the first cylinder and the second cylinder. A mast center spreader is thereafter removed from the lower mast section. A center drill floor section is removed from between the first substructure section and the second substructure section so that a combination of the first substructure section, the first cylinder and a portion of the lower mast and a combination of the second substructure section, the second cylinder and a portion of the lower mast may be transported. Another type of system is described in U.S. Patent Application No. 2012/0167485 issued to Mark W. Trevithick, et al. All of these documents are herein incorporated by reference for all that they contain.